India has long experienced a numerical shortage of females, and this sex ratio imbalance is likely to grow with the widespread adoption of sex-selective abortion technologies. Although considerable research has documented levels, trends, and differentials in India's population sex ratio, we know little about the consequences of India's imbalance in the numbers of women and men for critical family, demographic, and health-related behaviors. This project uses data from three different sources-the 2005-06 National Family Health Survey (NFHS-3), the 2004-05 India Human Development Survey (IHDS), and the 1981, 1991, and 2001 Censuses of India-to examine the impact of India's imbalanced population sex ratio on key family formation behaviors (e.g., age at marriage, fertility, likelihood of divorce, social and geographic exogamy, the values of dowries); on sexual behaviors and health outcomes (e.g., age at first sex, engagement in premarital and extramarital sex, number of sexual partners, commercial sex, forced sex, and contraction of sexually-transmitted disease, including HIV/AIDS); on gendered family dynamics (e.g., women's roles in household decision-making, other dimensions of women's empowerment and autonomy, domestic violence); and on women's socioeconomic attainment (e.g., women's literacy, educational attainment, labor force participation, occupational attainment). Multilevel fixed-effect and random-effect regression models will estimate the impact of the local marriage market sex ratio, measured with census data, on these outcomes measured in the NFHS-3 and the IHDS. By capitalizing on the substantial age-graded and geographic variation in adult sex ratios across India, and by applying statistical techniques appropriate for the analysis of multilevel data structures, the proposed analysis holds promise for substantially enhancing our understanding of how India's increasing overabundance of males relative to females will affect multiple dimensions of family life and population health.